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Discussion Starter #1
Hey guys my bike has been burning a lot of oil. Like, A LOT of oil. It leaks some too but on a 25mile ride i have to put in almost half a quart and I can fog up the main street of a quaint village in no time... Was hoping someone could help me figure out if it is the rings, or the valves, or if I should just do both while the engine is apart?



Just pulled the head off and this is the nightmare fuel horror movie scene that awaited:













Jontow said to flip the head upside down and fill it with PB BLaster to see if it leaks through. Going to do that tonight. Any other thoughts/suggestions besides "wow that's bad"?
This head has only been on here for a couple hundred miles, and I cleaned it and the valves/piston before installing
 

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I would say, that you will need new valve steam seals.



But you should also remove the rings and check the measurements

-> Manual page 4-30

->> out of spec -> change!
 

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Discussion Starter #3
Thanks Mac



If there is no significant scoring/glazing in the cylinder is it at all wise to just replace the rings and not doing anything else like honing/boring/replacing piston?
 

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The cylinder doesn't need to be honed, if there is no wearout.

-> you can still see the cross-grinding and no scraps are touchable



Some of my 125ccm divers has only changed the piston (is cheaper as to buy new rings, new clips, new pin) and the engine runs fine again.

-> The cylinder was in a good condition.





But check at first the condition of your cylinder/sleeve and the rings and than we can talk about the rest:

- new rings or not

- if new rings needed, hone or not

- sleeve OK? If not, new piston





After some hours of thinking (and a bit sleeping
) about it, I am really sure that you will need new valve steam seals.





@ NIQHOWIE

I think, that these "holes" are not holes.

It looks like different heights of the oil carbon/carbon deposit
 

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I say do everything -- new rings and new valve stem seals. And while you have it apart lap the valves. And don't forget a new late model cylinder base gasket.
 

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I say do everything -- new rings and new valve stem seals. And while you have it apart lap the valves. And don't forget a new late model cylinder base gasket.
were the rings put in properly. If you line up them so the ends are in line it would be a problem. Just a thought.
 

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I installed new rings on both or my TW's. I honed the cylinder and seated them per this guys instructions.



http://www.mototuneusa.com/break_in_secrets.htm



After 20 miles I changed the oil and it was loaded with metal flake. I have around 400 to 600 miles on each engine now and both seem to be running very well! Is this the best way to do it? I don't know. I don't think I would do this on a car engine -- way to much work to re do if it gets screwed up -- but on a simple engine like the TW200 if it has to be redone it is no big deal.
 

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Discussion Starter #11
Thanks guys, can I re-use the piston pin and circlips? This is getting expenssive....



Removed the jug the other day and there is no cross hatching left, and side gap on rings is out of spec. Sleeve measured out OK so it looks like I'm just going to put in some new rings and valve seals and hone the cylinder



Parts list:



Piston ring set $30.35

Valve Stem Seal (x2) $12.24

Valve guide (x2) $54.48

Head gasket $22.43

Base gasket $12.41





Tools list:



Flex-hone 65-67mm ball type hone $39.99

Flex-hone oil $9.50

Flex-hone cylinder wash brush $19.64

Tusk valve spring compressor $34.99





Total:

$258







Not sure this can happen any time soon. Do the valve guides need to be replaced or can just the seals be done? that would save a good bit of cash. Is my head gasket re-usable? It has only 200 miles on it...



Don't have anyone to borrow a valve spring compressor from...
 

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Just replace the seals -- I bet your guides are fine! (Clean valve stem and valve guide real well with carb cleaner. Lightly oil and insert into guide. There should be a teeny tiny amount of lateral movement. That is good enough.) Also buy your parts online. A lot cheaper. Rent a hone and use engine oil -- a $ 9.50 savings for oil. Wash with soap and water and use cheap ass scrub brush from hardware store. Wipe dry and spray with WD40 to prevent rust.



I bought my rings online from San Jose Yamaha. $23.48 Valve stem seals: $4.46 each. Cyl. head gasket $17.62 Cyl. base gasket $9.02.



Don't forget cyl. O-RING 93210-72529-00 $2.90



O-RING (5 per pack) 93210-13361-00 $1.34



GASKET 90430-14131-00 $2.07





Check ebay for hone and valve spring compressors.



http://www.sanjoseyamaha.com (I think S&H is $10)



http://www.partzilla.com/ (delivery a little slow).



You ought to be able to get it done for a lot less than $258.
 

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If you take the circlips off I would not reuse them. They would be fine if you do not spring them out of shape but if they come out while running it can get expensive fast.
 

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Discussion Starter #14
Thanks Tony and Arrowsmith



All the parts are here except the base gasket which should show up next week some time. Skipped the valve guides, hone oil and brush which makes perfect sense to me. Going to attempt to leave the piston in place.



Gotta leave town for work for a couple weeks but will let you know how it goes
 
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